Introduction to the Human Body Essay

Introduction to the Human Body Matching: Directions of the body Medial: Toward the midline of the body; opposite of lateral. Proximal: A structure is nearer to the trunk than is another part; opposite of distal. Distal: The part of the radius (arm bone) that is closer to the wrist than the elbow. Superior: The lung is above the diaphragm; above is described as… Anterior: Toward the front (the belly surface); another word is ventral. Matching: regional Terms Axillary: Armpit. Patellar: Kneecap area. Sternal: Breastbone area. Antecubital: Front part of the elbow area.

Flank: Fleshy area along the side between the ribs and the hip bone. Oral: Pertaining to the mouth. Lumbar: Lower back area extending from the chest to the hips. Buccal: Pertains to the space between the cheek and the gum. Inguinal: Groin region. Scapular: Shoulder blade area. Multiple Choices 1. This part of the humerus (upper arm bone) is closer to the elbow than to the axillary region. c) Distal 2. The lung is located in the thoracic cavity. Describe the relationship of the lung to the diaphragm. d) Superior 3. The umbilical area is located C) Inferior to the diaphragm 4.

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The sternal area is d) All of the above. (Superior to the diaphragm, the breastbone area, superficial to the mediastinum) 5. Which of the following is not descriptive of the mediastinum? B) Dorsal cavity a. Read Chapter 7: Integumentary System, Pages 90 to 105; b. Answer the questions Review Your Knowledge located in page 104 – 105 in your textbook. Matching: Skin Epidermis: Thin outer layer of the skin Dermis: Layer that sits on the hypodermis and supports the epidermis Keratin: A protein that flattens, hardens, and makes the skin water resistant Subcutaneous Layer: A layer of insulation

Epidermis: Contains the stratum germinativum and stratum corneum Matching: Glands Sebaceous: Oil glands; Glands that secrete vernix caseosa Eccrine: Gland that play a crucial role in body temperature regulation Ceruminous: Modified sweat glands that secrete ear wax Mammary: Modified sweat glands that secrete milk Matching: Colors Melanin: Tanning pigment Cyanosis: Condition in which the skin has a bluish tint because of poor oxygenation Jaundice: Yellowing of the skin because of bilirubin pigmentation Vitiligo: Patches of white skin due to loss of pigmentation

Ecchymosis: Black and blue mark Multiple Choices: 1. Which of the following is most apt to increase body temperature? b) Shivering 2. The stratum germinativum b) Gives rise to epidermal cells 3. The epidermis is nourished by the c) Blood vessels in the underlying dermis. 3. Which of the following is true of the stratum corneum? C) Is the dead layer that is sloughed off 5. Secretion of the Eccrine glands c) Lowers body temperature 6. Cyanosis occurs when a) The blood in the cutaneous blood vessels is unoxygenated c.

Answer the following questions about the Integumentary system. 1. Mention and explain extensively the major function of the Integumentary system. If it is uncomplicated for you answer this question as an essay (none less than 5 paragraphs. ) The Integumentary System, consisting of the skin, hair and nails, act as a barrier to protect the body from the outside world. It also has several other functions in the body. The word INTEGUMENT comes from a Latin word that means to cover. The most important function of the integumentary system is protection.

This system serves as a barrier against infection and injury, helps to regulate and maintain body temperature, removes waste products from the body, and provides protection against the sun’s ultraviolet radiation. The skin is a protective covering, also the largest organ in our body. It is composed of an epidermis and a dermis separated by a basement membrane. A subcutaneous layer, not part of the skin, lies beneath the dermis. The skin houses several different types of glands such as sweat glands, sebaceous glands, and apocrine glands. Nails are protective covers on the ends of fingers and toes.

They are produced by epidermal cells that undergo keratinization. Hair occurs in nearly all regions of the skin. Each hair develops from epidermal cells at the base of a tube like hair follicle. As newly formed cells develop and grow, older cells are pushed toward the surface to undergo keratinization. A bundle of smooth muscle cells and one or more sebaceous glands are attached to each hair. As stated, the integumentary system serves several different purposes in our body. It is a very vital system and it is needed for protection and stabilization inside and outside of the human body. . Describe the anatomical structure of the skin, Layers and their different stratums, functions, localization and distributions. The skin is an ever-changing organ that contains many specialized cells and structures. The skin functions as a protective barrier that interfaces with the environment. The skin helps the body in maintaining the proper temperature for the body to function well. Collect sensory information from the environment, and plays an active role in the immune system protecting the body from disease.

The skin functions are separate in the structure of the 3 layers of skin – the epidermis, dermis, and subcutaneous tissue. Epidermis: The epidermis is the outer layer of skin. The thickness of the epidermis varies in different types of skin. It is the thinnest on the eyelids at . 05 mm and the thickest on the palms and soles at 1. 5 mm. The epidermis contains 5 layers. From bottom to top the layers are named: stratum basale, stratum spinosum, stratum granulosum, stratum licidum, and stratum corneum. The bottom layer, the stratum basale, has cells that are shaped like columns.

In this layer the cells divide and push already formed cells into higher layers. As the cells move into the higher layers, they flatten and eventually die. The top layer of the epidermis, the stratum corneum, is made of dead, flat skin cells that shed about every 2 weeks. There are three types of specialized cells in the epidermis: The melanocyte produces pigment (melanin), the Langerhans’ cell is the frontline defense of the immune system in the skin, and the Merkel’s cell’s or Merkel-Ranvier cells are oval receptor cells found in the skin of vertebrates that have synaptic contacts with somatosensory afferents..

They are associated with the sense of light touch discrimination of shapes and textures. They can turn malignant and form the skin tumor known as Merkel cell carcinoma. Dermis: The dermis also varies in thickness depending on the location of the skin. It is . 3 mm on the eyelid and 3. 0 mm on the back. The dermis is composed of three types of tissue that are present throughout – not in layers. The types of tissue are: collagen, elastic tissue, and reticular fibers. The dermis has 2 layers: the papillary and reticular layers. The upper, papillary layer contains a thin arrangement of collagen fibers.

The lower, reticular layer is thicker and made of thick collagen fibers that are arranged parallel to the surface of the skin. The dermis contains many specialized cells and structures. The hair follicles are situated here with the erector pili muscle that attaches to each follicle. Sebaceous (oil) glands and apocrine (scent) glands are associated with the follicle. This layer also contains eccrine (sweat) glands, but they are not associated with hair follicles. Blood vessels and nerves course through this layer. The nerves transmit sensations of pain, itch, and temperature.

There are also specialized nerve cells called Meissner’s and Vater-Pacini corpuscles that transmit the sensations of touch and pressure. Subcutaneous Tissue: The subcutaneous tissue is a layer of fat and connective tissue that houses larger blood vessels and nerves. This layer is important is the regulation of temperature of the skin itself and the body. The size of this layer varies throughout the body and from person to person. If any of the structures in the skin are not working properly, a rash or abnormal sensation is the result. 3.

The skin is the home for several accessory structures, these are: glands, hair, and nail. Mention and describe their function, localizations, types of glands and their secretions, anatomical features, hormonal influence, Skin Glands: The skin of humans has two basic types of glands: sweat glands (sudoriferous) and oil glands (sebaceous). The sweat glands come in two varieties; the eccrine glands produce sweat all over our bodies, but the apocrine glands only become active during puberty and give us body odor. These aromatic apocrine glands are concentrated in the armpits and the genital regions.

The Hair: is a filamentous biomaterial that grows from follicles found in the dermis. The human body, apart from its glabrous skin, is covered in follicles which produce thick terminal and fine vellums hair. Hair often refers to two distinct structures: the part beneath the skin, called the hair follicle, This organ is located in the dermis and maintains stem cells which not only re-grow the hair after it falls out but also are recruited to regrow skin after a wound, and the shaft, which is the hard filamentous part that extends above the skin surface. Natural hair colors are the result of two types of hair pigment.

Both these pigments are types of melanin produced inside the hair follicle and packed into granules found in the fibers. Eumelanin is the dominant pigment in dark-blond, brown and black hair, while Pheomelanin is dominant in red hair. Blond hair is the result of having little pigmentation in the hair strand. Gray hair occurs when melanin decreases or disappears. Hair growth is influenced by the sex hormone estrogen and testosterone; Hair follows a specific growth cycle with three distinct and concurrent phases: Anagen, Catagen and Telogen phases. Each phase has specific characteristics that determine the length of the hair.

All three phases occur simultaneously; one strand of hair may be in the anagen phase, while another is in the telogen phase. Movements of hair shafts are detected by nerve receptors within the skin and by hair follicle receptors through displacement and vibration of hair shafts. Hairs can sense movements of air as well as touch by physical objects and are especially sensitive to the presence of insects. Some hairs are especially sensitive to the presence of potentially harmful matter, such as eyelashes. Nails: The fingernail is an important structure made of keratin that has 2 purposes.

The fingernail acts as a protective plate and enhances sensation of the fingertip. The protection function of the fingernail is commonly known, but the sensation function is equally important. The fingertip has many nerve endings in it allowing us to receive volumes of information about objects we touch. The nail acts as a counterforce to the fingertip providing even more sensory input when an object is touched. Nails grow all the time, but their rate of growth slows down with age and poor circulation. Fingernails grow faster than toenails at a rate of 3mm per month. It takes 6 months for a nail to grow from the root to the free edge.

Toenails grow about 1 mm per month and take 12-18 months to be completely replaced. 4. The normal body temperature is said to be 98. 6 F. To maintain this temperature the human body need some special regulatory function, Mention and describe this several regulatory mechanisms. In humans, body temperature is controlled by the thermoregulatory center in the hypothalamus. It receives input from two sets of thermo receptors: receptors in the hypothalamus itself monitor the temperature of the blood as it passes through the brain (the core temperature), and receptors in the skin (especially on the trunk) monitor the external temperature.

Both sets of information are needed so that the body can make appropriate adjustments. The thermoregulatory center sends impulses to several different effectors to adjust body temperature. The first response to encountering hotter or colder condition is voluntary, if too hot, we may decide to take some clothes off, or to move into the shade; if too cold, we put extra clothes on or turn the heating up! It is only when these responses are not enough that the thermoregulatory centre is stimulated. This is part of the autonomic nervous system, so the various responses are all involuntary.

When we get too hot, the heat loss centre in the hypothalamus is stimulated; when we get too cold, it is the heat conservation centre of the hypothalamus which is stimulated. Some of the responses to low temperature actually generate heat (thermogenesis), whilst others just conserve heat. Similarly some of the responses to cold actively cool the body down, while others just reduce heat production or transfer heat to the surface. The body thus has a range of responses available, depending on the internal and external temperatures.